When two defendants are sued for one tort and one co-defendant seeks summary judgment, who has standing to oppose the motion? Obviously the plaintiff has standing to oppose, but what about the other co-defendant? Even supposing the co-defendant has standing if the plaintiff opposes, is that standing contingent on the plaintiff’s opposition? Current jurisprudence in federal courts and prior scholarship are scarce and in disagreement which leaves parties without ground on which to base their answers. A simple answer to this quandary might assume parties sitting on the same side of a case may not oppose one another (in the absence of cross-claims). This article contends that sides of the case on which parties sit are an inappropriate focal point. The focus should instead be on which side of a particular controversy parties stand. Individuals opposed to co-party motions should have the opportunity to oppose because the operative criterion is adversity of position.

The minimal judicial consensus and legal literature discussing such a scenario creates prediction problems for litigators in multi-party litigation. The lack of certainty may generate confusion or even conflict between co-parties seeking to advance a common objective – winning the lawsuit – while simultaneously advancing their own unique interests – minimizing costs and damages for a particular client. The unique interests can create a prisoner’s dilemma in which minimizing one party’s losses may maximize a co-party’s. This article seeks to build a theory upon which future legal consensus on co-party standing to oppose motions might be developed.

This article derives and applies principles from appellate standing and the right of intervention to support permitting co-party opposition to motions. The “aggrieved” standard of appellate standing and intervention’s justifications of “adequate representation” and “unique perspective” inform the otherwise minimal development of a theory permitting co-party motion opposition. Permitting opposition to co-defendant motions by co-parties would provide predictability and ensure parties have their voices heard on issues of interest without sacrificing courtroom efficiency.